Microturning of landing gear components used in miniature unmanned aircraft vehicles

2018 ◽  
Vol 1 (1) ◽  
pp. 20-44 ◽  
Author(s):  
M. J. Jackson ◽  
J. Burgess

The microturning of landing gear components used in miniature unmanned aircraft vehicles is described in this article. The finite element method (FEM) is used to predict variables such as microturning forces and temperatures at two different levels of roughing cut (1 and 3 mm depth of cut) with variable geometry cutting tool inserts. The predicted results are compared to experimentally determined magnitudes of forces and temperatures using a dynamometer and an infrared thermal camera. The results show that tool inserts with novel chip breaker functions reduce the magnitude of the machining forces and temperatures predicted using the FEM and validated by performing controlled experiments using Al-380 aluminum alloys machined with polycrystalline diamond-coated cutting tool inserts.

2012 ◽  
Vol 591-593 ◽  
pp. 476-479
Author(s):  
Xu Xing Jin

Silicon wafer is machined by diamond cutting tools to certain extent, the cutting tool currently used is polycrystalline diamond (PCD). However, as its cutting edges are not leveled to the same height, it will produce different depth of cut and the stress distribution is uneven on wafer surfaces, in the process of wafer thinning, both the workpiece and the cutting tool are probably damaged, this will increase the production cost accordingly. In this paper, a strategy is described to improve the ability of cutting tool for wafer thinning, a cutting tool named Ultimate Diamond Disk (UDD) designed by Taiwan Wheel Company is recommended, which can reduce both the crack of workpiece and the wear speed of cutting tool. Moreover, an experiment on base of different machining parameters including rotation speed of spindle, feed rate and depth of cut was tested and discussed. As a result, the removal mode of workpiece material and the wafer thinning characteristics of UDD are obtained.


Mechanik ◽  
2017 ◽  
Vol 90 (2) ◽  
pp. 128-132
Author(s):  
Piotr Putyra ◽  
Lucyna Jaworska ◽  
Maciej Dyzia ◽  
Marcin Podsiadło

The stability of PCD inserts in the machining of cast composite materials containing 10 vol.% of ceramic phase is presented. Tests were carried out using a polycrystalline diamond cutting tool and the turning and milling center Mori Seiki NL2000SY. The VBB wear parameters of inserts according to the standard PN-ISO 3685:1996 were determinated. The influence of the cutting parameters (speed, feed rate, depth of the cut) on the temperature of PCD inserts was investigated. The analysis of chip formation mechanism during the processing at different cutting parameters was performed. The study was carried out using the FLIR A655 thermal camera and the high speed camera Phantom MIRO M310.


1989 ◽  
Vol 111 (1) ◽  
pp. 1-6
Author(s):  
J. E. Geier ◽  
M. Hood

Empirical models are developed to describe the influence on the cutting process of preweakening a rock, by cutting a series of parallel kerfs in the surface with high pressure waterjets, prior to excavating the rock with a polycrystalline diamond compact (PDC) drag bit. These models show that both the bit cutting force and the bit normal force are reduced substantially (by as much as a factor of four) when the spacing and the depth of the kerfs is appropriate to the depth of cut taken by the bit. The mechanical specific energy, or the mechanical energy applied to the bit to excavate a unit volume of rock, is also reduced dramatically when the rock is prekerfed.


Because of multiple properties like higher values of corrosion resistance, formability, weldability along with greater structural utility aluminum alloys are generally gaining more and more demand in industries and household. With this the requirement for searching of higher quality cutting tool to machine aluminum is also growing. Here different cutting tools like MTCVD+TiCN+Al2O3 , MTCVD+TiCN+Al2O3+TiOCN, MTCVD+TiN+TiCN+Al2O3+TiN, PVD AlTiN, cemented carbide (k-10) insert brazed with Polycrystalline Diamond and Polycrystalline Diamond Inserts are being used to machine rolled aluminum in dry condition and then comparative analysis are made. The cutting is of orthogonal type and capstan lathe is used for the same. Under different conditions of cutting the surface roughness along with morphology of chip are analyzed. Under constant depth of cut (doc) along with variable velocities and feed, the turning operation is performed. With SEM and XRD the identification including characterization of cutting tool were also performed. The polycrystalline diamond tool is found to give optimum surface finish, thin type of chip along with mirror like finish during machining operation.


2021 ◽  
Vol 11 (11) ◽  
pp. 4743
Author(s):  
Fernando Cepero-Mejias ◽  
Nicolas Duboust ◽  
Vaibhav A. Phadnis ◽  
Kevin Kerrigan ◽  
Jose L. Curiel-Sosa

Nowadays, the development of robust finite element models is vital to research cost-effectively the optimal cutting parameters of a composite machining process. However, various factors, such as the high computational cost or the complicated nature of the interaction between the workpiece and the cutting tool significantly hinder the modelling of these types of processes. For these reasons, the numerical study of common machining operations, especially in composite machining, is still minimal. This paper presents a novel approach comprising a mixed multidirectional composite damage mode with composite edge trimming operation. An ingenious finite element framework which infer the cutting edge tool wear assessing the incremental change of the machining forces is developed. This information is essential to replace tool inserts before the tool wear could cause severe damage in the machined parts. Two unidirectional carbon fibre specimens with fibre orientations of 45∘ and 90∘ manufactured by pre-preg layup and cured in an autoclave were tested. Excellent machining force predictions were obtained with errors below 10% from the experimental trials. A consistent 2D FE composite damage model previously performed in composite machining was implemented to mimic the material failure during the machining process. The simulation of the spring back effect was shown to notably increase the accuracy of the numerical predictions in comparison to similar investigations. Global cutting forces simulated were analysed together with the cutting tool tooth forces to extract interesting conclusions regarding the forces received by the spindle axis and the cutting tool tooth, respectively. In general terms, vertical and normal forces steadily increase with tool wear, while tangential to the cutting tool, tooth and horizontal machining forces do not undergo a notable variation.


1996 ◽  
Vol 11 (7) ◽  
pp. 1765-1775 ◽  
Author(s):  
James M. Olson ◽  
Michael J. Dawes

Thin diamond film coated WC-Co cutting tool inserts were produced using arc-jet and hot-filament chemical vapor deposition. The diamond films were characterized using SEM, XRD, and Raman spectroscopy to examine crystal structure, fracture mode, thickness, crystalline orientation, diamond quality, and residual stress. The performance of the tools was evaluated by comparing the wear resistance of the materials to brazed polycrystalline diamond-tipped cutting tool inserts (PCD) while machining A390 aluminum (18% silicon). Results from the experiments carried out in this study suggest that the wear resistance of the thin diamond films is primarily related to the grain boundary strength, crystal orientation, and the density of microdefects in the diamond film.


2017 ◽  
Vol 749 ◽  
pp. 107-110
Author(s):  
Yuta Masu ◽  
Tomohito Fukao ◽  
Taiga Yasuki ◽  
Masahiro Hagino ◽  
Takashi Inoue

The method of imparting ultrasonic vibration to the cutting tool is known to improve the shape accuracy and finished surface roughness. However, a uniform evaluation of this function in drilling has not been achieved, and the cutting process cannot be checked from the outside. The aim of this study is to investigate the cutting characteristics in deep hole drilling when an ultrasonic vibrator on the table of a machining center provides vibration with a frequency of 20 kHz to the work piece. The ultrasonic vibrations in this system reach the maximum amplitude in the center of the work material. We evaluated the change in finished surface roughness between the section where drilling starts to the point of maximum amplitude with ultrasonic vibration. The main cutting conditions are as follows: cutting speed (V) 12.6 (mm/min); feed rate (s) 30, 60 (mm/rev); depth of cut (t) = 32 (mm); work material, tool steel; cutting tool material, HSS; point angle (σ) 118 (°); and drill diameter (φ) 4 (mm). Lubricant powder was also added to clarify the cutting effect, and compared the condition in which there was no ultrasonic vibration. The results showed that surface roughness at the point of maximum amplitude was better than that with no vibration.


1985 ◽  
Vol 107 (2) ◽  
pp. 99-106 ◽  
Author(s):  
R. Komanduri ◽  
M. Lee

The salient features of a simple, wear-tolerant cemented carbide tool are described. Results are presented for high-speed machining (3 to 5 times the conventional speeds) of titanium alloys in turning and face milling. This tool, termed the ledge cutting tool, has a thin (0.015 to 0.050 in.) ledge which overhangs a small distance (0.015 to 0.060 in.) equal to the depth of cut desired. Such a design permits only a limited amount of flank wear (determined by the thickness of the ledge) but continues to perform for a long period of time as a result of wear-back of the ledge. Under optimum conditions, the wear-back occurs predominantly by microchipping. Because of geometric restrictions, the ledge tool is applicable only to straight cuts in turning, facing, and boring, and to face milling and some peripheral milling. Also, the maximum depth of cut is somewhat limited by the ledge configuration. In turning, cutting time on titanium alloys can be as long as ≈ 30 min. or more, and metal removal of ≈ 60 in.3 can be achieved on a single edge. Wear-back rates in face milling are about 2 to 3 times higher than in straight turning. The higher rates are attributed here to the interrupted nature of cutting in milling. Use of a grade of cemented carbide (e.g., C1 Grade) which is too tough or has too thick a ledge for a given application leads to excessive forces which can cause gross chipping of the ledge (rapid wear) and/or excessive deflection of the cutting tool with reduced depth of cut. Selection of a proper grade of carbide (e.g., Grades C2, C3, C4) for a given application results in uniform, low wear-back caused by microchipping. Because of the end cutting edge angle (though small, ≈ 1 deg) used, the ledge tool can generate a slight taper on very long parts; hence an N.C. tool offset may be necessary to compensate for wear-back. The ledge tool is found to give excellent finish (1 to 3 μm) in both turning and face milling. In general, conventional tooling with slight modifications can be used for ledge machining. The ledge tool can also be used for machining cast iron at very high speeds.


1997 ◽  
Vol 119 (4A) ◽  
pp. 494-501 ◽  
Author(s):  
D. A. Stephenson ◽  
T.-C. Jen ◽  
A. S. Lavine

This paper describes a model for predicting cutting tool temperatures under transient conditions. It is applicable to processes such as contour turning, in which the cutting speed, feed rate, and depth of cut may vary continuously with time. The model is intended for use in process development and trouble shooting. Therefore, emphasis is given in the model development to enable rapid computation and to avoid the need to specify parameters such as thermal contact resistances and convection coefficients which are not known in practice. Experiments were conducted to validate the predictive model. The model predictions with two different boundary conditions bound the experimental results. An example is presented which shows the utility of the model for process planning.


2017 ◽  
Vol 54 (1) ◽  
pp. 180-179 ◽  
Author(s):  
Raul Cormos ◽  
Horia Petrescu ◽  
Anton Hadar ◽  
Gorge Mihail Adir ◽  
Horia Gheorghiu

The main purpose of this paper is the study the behavior of four multilayered composite material configurations subjected to different levels of low velocity impacts, in the linear elastc domain of the materials, using experimental testing and finite element simulation. The experimental results obtained after testing, are used to validate the finite element models of the four composite multilayered honeycomb structures, which makes possible the study, using only the finite element method, of these composite materials for a give application.


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